Diversity of Methylobacterium Species Associated with New Zealand Native Plants

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Citation

Jahan, R. (2013). Diversity of Methylobacterium Species Associated with New Zealand Native Plants (Thesis, Master of Science (MSc)). University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/7562

Abstract

The genus Methylobacterium are pink-pigmented facultative methylotrophs (PPFMs), and are abundant colonizers of the phyllosphere, due to the availability of methanol, a waste product of pectin metabolism during plant cell division. Besides methanol cycling, Methylobacterium has important effects on plant health. The phyllosphere is an extreme environment with a landscape that is heterogeneous, continuously changing as the plant grows, and is exposed to very high ultra violet irradiation. Geographically, New Zealand has been isolated for over a million years, has a biologically diverse group of species, and is considered a biodiversity hotspot, with most of the native plants being endemic. We hypothesize that NZ native plants harbor diverse groups of Methylobacterium species, and to test this we aimed to isolate Methylobacterium species from the phyllosphere of native New Zealand plants. A leaf imprinting technique using methanol supplemented AMS agar media was used to isolate bacteria and diversity was determined using a combination of ARDRA, 16S rRNA gene sequencing and phylogenetic analysis. Methylobacterium spp. were successfully isolated from 19 of the 21 plant species used in this study. Eleven Methylobacterium species have been identified in association with the phyllosphere of native NZ plants: M. adhaesivum, M. brachiatum, M. komagatae, M. marchantiae, M. mesophilicum, M. phyllosphaerae, M. fujisawaense, M. oryzae, M. radiotolerans, M. tardum and M. zatmanii, with the first six being the most frequently isolated from more plant species. In this study other α, β, γ-proteobacterial species were also isolated: Hyphomicrobium, Methylopila, Rhizobium, Achromobacter, Methylophilus, Ramlibacter and Xanthomonas; Janibacter melonis (Actinomycetes); Niastella populi (Bacteroidetes) and Paenibacillus lautus (Firmicutes), highlighting the presence of potential novel methanol utilizer within the ecosystem. Results from this study indicate that Methylobacterium are abundant and dominant members of the NZ phyllosphere environment, with species diversity and composition dependent on the host plant species.